Memory device

ABSTRACT

The present disclosure, in some embodiments, relates to an integrated circuit. The integrated circuit includes a dielectric protection layer disposed over a dielectric structure that laterally surrounds one or more conductive interconnect layers. The dielectric protection layer has a protrusion extending outward from an upper surface of the dielectric protection layer. A bottom electrode is disposed over the dielectric protection layer and has sidewalls extending outward from a lower surface of the bottom electrode through the dielectric protection layer. The bottom electrode has a substantially planar upper surface over the protrusion. A data storage element is over the substantially planar upper surface of the bottom electrode, and a top electrode is over the data storage element.

REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No.15/393,892, filed on Dec. 29, 2016, which claims priority to U.S.Provisional Application No. 62/402,132, filed on Sep. 30, 2016. Thecontents of the above-identified patent applications are herebyincorporated by reference in their entirety.

BACKGROUND

Many modern electronic devices contain electronic memory configured tostore data. Electronic memory may be volatile memory or non-volatilememory. Non-volatile memory is able to store data in the absence ofpower, whereas volatile memory is not. Magnetoresistive random-accessmemory (MRAM) and resistive random access memory (RRAM) are promisingcandidates for next generation non-volatile memory technology due torelative simple structures and their compatibility with complementarymetal-oxide-semiconductor (CMOS) logic fabrication processes.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a cross-sectional view of some embodiments of amemory device having a single bottom electrode structure comprising abottom electrode region and a bottom electrode via region.

FIG. 2A illustrates a cross-sectional view of some alternativeembodiments of a memory device having a single bottom electrodestructure comprising a bottom electrode region and a bottom electrodevia region.

FIG. 2B illustrates a cross-sectional view of some other embodiments ofa memory device having a single bottom electrode structure.

FIGS. 3A-3B illustrate cross-sectional view of some additionalembodiments of memory devices having a single bottom electrodestructure.

FIG. 4 illustrates a cross-sectional view of some embodiments of anintegrated circuit (IC) having a memory region and a periphery logicregion.

FIGS. 5-14 illustrate cross-sectional views of some embodiments showinga method of manufacturing a memory device having a single bottomelectrode structure comprising a bottom electrode region and bottomelectrode via region.

FIG. 15 illustrates a flow diagram of some embodiments of a method ofmanufacturing a memory device having a single bottom electrode structurecomprising a bottom electrode region and bottom electrode via region.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

A trend in semiconductor manufacturing is to integrate different typesof devices on a single substrate to achieve higher integration. Forexample, a logic region and a memory region may be formed on a singlesubstrate. In some embodiments, the memory region may comprise amagnetic random access memory (MRAM) device or a resistive random accessmemory (RRAM) device. MRAM and RRAM devices comprise memory cells havingresistive elements that are vertically arranged within aback-end-of-the-line (BEOL) metal stack between a bottom electrode and atop electrode.

To form an MRAM or RRAM memory cell, a bottom electrode via layer isoverfilled into an opening in an underlying dielectric layer. Theopening typically has a high aspect ratio which can lead to defectsduring filling. For example, gap-fill seams and grain growth limitationdefects may be present in the bottom electrode via layer. After filling,a first chemical mechanical planarization (CMP) process can be used toplanarize the bottom electrode via layer to form a bottom electrode via(BEVA) within the opening. A bottom electrode layer is subsequentlyformed over the BEVA. A second CMP process is then performed on thebottom electrode layer to form a bottom electrode upon which a memoryelement is subsequently formed.

The defects during filling can prevent the first and second CMPprocesses from giving the bottom electrode a planar upper surface,thereby resulting in an abnormal memory element interface that reducesyield and degrades IC performance. While certain conductive materials,such as copper, may not succumb to defects during filling, thesematerials are undesirable since they suffer from iso-denseelectroplating issues and CMP corrosion issues. Furthermore, a peripherylogic region may be damaged by the CMP processes within a memory region.For example, the bottom electrode layer of the memory region has ahigher structural integrity than metal interconnect lines within theperiphery logic region. When the bottom electrode layer of the memoryregion is exposed to a CMP process, the metal interconnect of the logicregion is also exposed. Because the metal interconnect line isstructurally weaker than the bottom electrode, performing a CMP processon the bottom electrode layer can cause “dishing” of the metalinterconnect lines in the logic region, further degrading thereliability of the resultant IC.

The present disclosure relates to a memory device having bottomelectrode region and bottom electrode via region that comprise a singlelayer (e.g., a continuous, seamless layer of conductive material), andassociated fabrication methods. To form the memory device, an opening isformed in a dielectric protection layer. The opening is overfilled witha bottom electrode layer. The BEVA is formed in the opening from thebottom electrode layer and the overfill of the bottom electrode layer isplanarized to form a planarized bottom electrode layer having a bottomelectrode region and a bottom electrode via (BEVA) region. Accordingly,the transition between the BEVA region and the bottom electrode regionis seamless. A memory element (e.g., a MTJ or RRAM cell) is formed overthe planarized bottom electrode layer. By forming the BEVA region andthe bottom electrode region as one layer, planarization problems aremitigated and the fabrication methods are simplified and more efficient.As a result, risk of damaging the lower metal lines is reduced, therebyproviding more reliable read/write operations and/or better performance.

FIG. 1 illustrates a cross-sectional view of some embodiments of amemory device having a single bottom electrode structure comprising abottom electrode region and a bottom electrode via region.

The memory device 114 is arranged over a substrate 102. In someembodiments, the substrate 102 may comprise a semiconductor material,such as for example, a silicon substrate. An inter-layer dielectric(ILD) layer 104 is arranged over the substrate 102. The ILD layer 104surrounds a plurality of metal layers 106 including a metal line 106 aand a metal via 106 b. The plurality of metal layers 106 may becomprised of a conductive material such as copper.

A dielectric protection layer 108 is arranged over the ILD layer 104.The dielectric protection layer 108 includes an opening 108 a thatextends through the dielectric protection layer 108 to an underlying oneof the plurality of metal layers 106. In various embodiments, theopening 108 a is arranged over the metal line 106 a or a metal via 106 b(not shown). A passivation layer 110 acts as a diffusion barrier andincludes passivation layers 110 a and 110 b. In some embodiments, thepassivation layer 110 may comprise tantalum nitride (TaN), titaniumnitride (TiN), a dielectric material such as TEOS (TetraethylOrthosilicate), or combinations thereof.

Passivation layer 110 a is conformally disposed around at least aportion of metal layers 106. For example, the passivation layer 110 amay be in direct contact with the metal line 106 a. Passivation layer110 b is disposed conformally over the dielectric protection layer 108and lines the opening 108 a. In various embodiments, the dielectricprotection layer 108 may extend outward from the opening 108 a or may beconfined within the opening 108 a. The dielectric protection layer 108may comprise silicon carbide, silicon nitride, or combinations thereof.

A bottom electrode structure 112 is arranged over the passivation layer110 b. The bottom electrode structure 112 overfills the opening 108 aand overlies the passivation layer 110 b. The bottom electrode structure112 comprises both a bottom electrode via (BEVA) region 112 a and abottom electrode region 112 b. The BEVA region 112 a comprises aprojection extending outward from a lower surface of the bottomelectrode region 112 b to a position that is surrounded by thedielectric protection layer 108. The bottom electrode region 112 bextends past opposing sides of the BEVA region 112 a and comprises aplanar upper surface. A height of the BEVA region 112 a extends from abottom surface of the bottom electrode structure 112 to a top surface ofthe passivation layer 110 b and a height of the bottom electrode region112 b extends between the top surface of the passivation layer 110 b andthe top surface of the bottom electrode structure 112.

The memory device 114 further comprises a memory element 116 arrangedover the bottom electrode region 112 b and a top electrode 118 arrangedover the memory element 116. In some embodiments, the bottom electrodestructure 112 comprises a single layer of material that continuouslyextends from a surface of the passivation layer 110 b within the opening108 a to a bottom surface of the memory element 116. For example, insome embodiments, the bottom electrode structure 112 may comprise ametal nitride layer, such as titanium nitride (TiN), which continuouslyextends from the passivation layer 110 b within the opening 108 a tocontact a bottom surface of the memory element 116. In otherembodiments, the bottom electrode structure 112 may comprise a tungsten(W) layer that continuously extends from the passivation layer 110 bwithin the opening 108 a to contact a bottom surface of the memoryelement 116.

In some embodiments, the sidewalls of the bottom electrode region 112 bare substantially vertical. In other embodiment, the bottom electroderegion 112 b may have planar top and bottom surfaces and tiltedsidewalls. In some embodiments, the memory element 116 may comprise amagnetic tunnel junction (MTJ) of a magnetoresistive random-accessmemory (MRAM) cell. In other embodiments, the memory element 116 maycomprise a dielectric data storage layer of a resistive random accessmemory (RRAM) cell.

Because the BEVA region 112 a and the bottom electrode region 112 b arecomprised within a single bottom electrode structure 112, there is noseam interface and/or grain boundaries located between the BEVA region112 a and the bottom electrode region 112 b, thereby eliminating fillingdefects that may otherwise degrade performance and reduce scalability ofthe memory device. Furthermore, using one bottom electrode structure 112simplifies the manufacturing process because the BEVA region 112 a andthe bottom electrode region 112 b do not require separate deposition andplanarization processes. Therefore, in addition to improving operationof the memory device 114, the fabrication methods are simplified andmore efficient.

FIG. 2A illustrates a cross-sectional view 200 of other embodiments of amemory device 114 having a bottom electrode structure 112 comprising asingle layer having a BEVA region 112 a and a bottom electrode region112 b. The substrate 102, the ILD layer 104, the metal layers 106including the metal line 106 a and the metal via 106 b, the dielectricprotection layer 108, the passivation layer 110, and the bottomelectrode structure 112 operate in a similar manner as described above.

In some embodiments, the top electrode 118 comprises one or moreconductive layers overlying the memory element 116. In some embodiments,the top electrode 118 may comprise a first top electrode layer 120 and asecond top electrode layer 122 comprising a different material than thefirst top electrode layer 120. In some additional embodiments, the topelectrode 118 may further comprise a hard mask layer 124 over the secondtop electrode layer 122, and a third top electrode layer 126 over thehard mask layer 124. In some embodiments, the first top electrode layer120, the second top electrode layer 122, and the third top electrodelayer 126 may be comprised of conductive materials such as titaniumnitride (TiN), tantalum nitride (TaN), tantalum (Ta), and/or titanium(Ti), or combinations thereof. The hard mask layer 124 may be comprisedof silicon nitride (SiN). In some embodiments, an upper portion of thememory device 114 is surrounded by a dielectric spacer layer 128.

FIG. 2B illustrates a cross-sectional view 250 of some alternativeembodiments of a memory structure 208.

The memory structure 208 comprises a bottom electrode structure 112having a BEVA region 112 a and bottom electrode region 112 b. The bottomelectrode structure 112 is arranged within and over a dielectricprotection layer 108, which overlies a metal via 202 arranged within anILD layer 104. In some embodiments, the metal via 202 may be comprisedof a conductive material, such as copper. In some embodiments, thedielectric protection layer 108 may comprise a single layer of siliconcarbide. In other embodiments, the dielectric protection layer 108 maycomprise a stack of different dielectric materials. For example, in someembodiments, the dielectric protection layer 108 may comprise a stackcomprising a layer of silicon carbide and a layer of silicon-rich oxidedisposed on the layer of silicon carbide.

To keep the conductive material from diffusing in the ILD layer 104, themetal via 202 may be separated from the ILD layer 104 by a diffusionbarrier layer 204. The diffusion barrier layer 204 may have diffusionbarrier protrusions 204 a/204 b that protrude outward into the overlyingdielectric protection layer 108. The diffusion barrier protrusions 204a/204 b result in dielectric protection layer protrusions 206 a/206 band passivation protrusions 208 a/208 b laterally arranged over thediffusion barrier protrusions 204 a/204 b, respectively. The passivationprotrusions 208 a/208 b cause the bottom electrode region 112 b to havedepressions within a lower surface facing the substrate 102, while anupper surface of the bottom electrode region 112 b facing an oppositedirection than the lower surface is substantially planar.

Although FIGS. 1, 2A, and 2B illustrates an “on-axis” BEVA, it will beappreciated that the disclosed memory devices may also comprise an“off-axis” BEVA, such that the BEVA region 112 a is aligned according toa bottom electrode axis while the memory element 116 and the topelectrode 118 are aligned according to a top electrode axis that has ahorizontal shift with respect to the bottom electrode axis.

FIGS. 3A-3B illustrate cross-sectional views, 300 and 304, of variousembodiments of a memory device 114 having a resistive switching element.

As shown in cross-sectional view 300 of FIG. 3A, a memory device 302 isarranged over a substrate 102. The memory device 302 comprises a bottomelectrode structure 112 extending from within a dielectric protectionlayer 108 to an overlying resistive switching layer 304. The resistiveswitching layer 304 comprises a dielectric data storage layer arrangedbetween the bottom electrode structure 112 and a top electrode 118. Thetop electrode 118 is further coupled to an overlying upper metal via308, which extends through the dielectric spacer layer 128.

The dielectric data storage layer has a variable resistance value thatdepends upon conductive filaments 306, comprising a chain of oxygenvacancies, which may extend through the dielectric data storage layer.In some embodiments, the dielectric data storage layer may comprise ahigh-k dielectric layer. For example, in various embodiments, thedielectric data storage layer nickel oxide (NiO), titanium oxide (TiO),hafnium oxide (HfO), zirconium oxide (ZrO), zinc oxide (ZnO), tungstenoxide (WO₃), aluminum oxide (Al₂O₃), tantalum oxide (TaO), molybdenumoxide (MoO), and/or copper oxide (CuO), for example.

As shown in cross-sectional view 310 of FIG. 3B, a memory device 312 isarranged over a substrate 102. The memory device 312 comprises a bottomelectrode structure 112 extending from within a dielectric protectionlayer 108 to an overlying resistive switching layer 314 comprising amagnetic tunnel junction (MTJ) vertically arranged between the bottomelectrode structure 112 and a top electrode 118. The MTJ comprises apinned magnetic layer 316 and a free magnetic layer 320, which arevertically separated by a dielectric barrier layer 318. In someembodiments, an anti-ferromagnetic layer (not shown) may be arrangedbetween the bottom electrode structure 112 and the pinned magnetic layer316. The magnetic orientation of the pinned magnetic layer 316 is static(i.e., fixed), while the magnetic orientation of the free magnetic layer320 is capable of switching between a parallel configuration withrespect to that of the pinned magnetic layer 316 and an anti-parallelconfiguration. The parallel configuration provides for a low resistancestate that digitally stores data as a first bit value (e.g., a logical“0”). The anti-parallel configuration provides for a high resistancestate that digitally stores data as a second bit value (e.g., a logical“1”).

In some embodiments, the anti-ferromagnetic layer may comprise iridiummanganese (IrMn), iron manganese (FeMn), ruthenium manganese (RuMn),nickel manganese (NiMn), and/or palladium platinum manganese (PdPtMn).In some embodiments, the pinned magnetic layer 316 may comprise a firstferromagnetic layer including cobalt (Co), iron (Fe), boron (B), and/orruthenium (Ru). In some embodiments, the dielectric barrier layer 318may comprise a tunnel barrier layer including magnesium oxide (MgO)and/or aluminum oxide (Al₂O₃). In some embodiments, the free magneticlayer 320 may comprise a second ferromagnetic layer including cobalt(Co), iron (Fe), and/or boron (B).

FIG. 4 illustrates a cross-sectional view 400 of some embodiments of anintegrated circuit (IC) having a memory region 402 and a periphery logicregion 404. The memory region 402 and the periphery logic region 404 arearranged over the substrate 102. The memory region 402 comprises amemory device 114 having a bottom electrode structure 112 arranged overa passivation layer 110 within a dielectric protection layer 108 that isdisposed over a metal via 106 b. The periphery logic region 404comprises a bottom via layer 408 that extends from a lower metal layer406 to an intermediate metal wire layer 410 laterally offset from thememory device 114. In some embodiments, the bottom via layer 408 extendsfrom the lower metal layer 406 to a position that is aligned with a topsurface of metal via 106 b. A first upper metal via 412 is coupled tothe memory device 114, and a second upper metal via 414 is coupled tothe intermediate metal wire layer 410. In some embodiments, an upperetch stop liner 420 and/or a protective liner 422 are disposedsurrounding a portion of the upper metal vias 412, 414.

In some embodiments, the bottom via layer 408 has a height that islarger than a height of the metal via 106 b. In some embodiments, thelarger height of the bottom via layer 408 causes the bottom via layer408 to have an upper surface that is co-planar with a top surface of thepassivation layer 110. Because the bottom electrode structure 112 is asingle conductive layer, a single CMP process may be used to form theupper surface of the bottom electrode structure 112. The use of a singleCMP process prevents damage to the periphery logic region 404 (e.g.,dishing of the bottom via layer 408), which would occur using a separateCMP process to form the BEVA region 112 a. In other words, by formingthe BEVA region 112 a and the bottom electrode region 112 b from asingle layer, additional BEVA planarization and/or patterning processesare not needed. Because the planarization and/or patterning processes ofthe memory region 402 can degrade the periphery logic region 404,reducing the amount of the planarization and/or patterning processesreduces the risk to the periphery logic region 404, thereby providingmore reliable read/write operations and/or better performance.

FIGS. 5-14 illustrate some embodiments of cross-sectional views showinga method of forming a memory device having a single layer BEVA andbottom electrode.

As shown in cross-sectional view 500 of FIG. 5, a lower ILD layer 104 isformed over a substrate 102. The lower ILD layer 104 includes aplurality of metal layers 106 such as metal line 106 a and metal via 106b. In some embodiments, the plurality of metal layers 106 are formed byforming a lower ILD layer 104 (e.g., an oxide, a low-k dielectric, or anultra low-k dielectric) over the substrate 102, followed by a damasceneprocess to form openings within the lower ILD layer 104 and fill a metalmaterial (e.g., copper, aluminum, etc.) into the openings. Aplanarization process can be then performed to remove excess metalmaterial to form the plurality of metal layers 106.

A dielectric protection layer 108 is formed over the lower ILD layer104. In some embodiments, the dielectric protection layer 108 may becomprised of silicon-nitride (SiN), silicon-carbide (SiC), or a similarcomposite dielectric film. In some embodiments, the dielectricprotection layer 108 may be approximately 30 nanometers thick. Thedielectric protection layer 108 may be formed by one or more depositionprocesses (e.g., physical vapor deposition, chemical vapor deposition,etc.).

As shown in cross-sectional view 600 of FIG. 6, a mask layer 602 isformed and patterned over the dielectric protection layer 108. Anetching process 604 is performed through an etch opening 606 in the masklayer 602 to pattern the dielectric protection layer 108. In someembodiments, the mask layer 602 can be a photoresist layer. In someembodiments, the etch opening 606 allows a dry etch process, such as aplasma etching, to reach the dielectric protection layer 108.

As shown in cross-sectional view 700 of FIG. 7, the mask layer 602,shown in FIG. 6 is removed leaving an opening 108 a in the dielectricprotection layer 108 that corresponds to the etch opening 606 shown inFIG. 6. The opening 108 a may comprise a low aspect ratio opening. Forexample, in some embodiments, the opening 108 a may have a greater width(direction parallel to top surface of substrate 102) than height(direction perpendicular to top surface of substrate 102). The lowaspect ratio of the opening 108 a reduces gap fill issues duringsubsequent processing steps.

As shown in cross-sectional view 800 of FIG. 8, a passivation layer 110is conformally deposited over the dielectric protection layer 108 andwithin the opening 108 a. In some embodiments, the passivation layer 110may be comprised of tantalum (Ta) or tantalum nitride (TaN). In otherembodiments, the passivation layer 110 may be comprised of siliconnitride, tetraethyl orthosilicate (TEOS), silicon-rich oxide (SRO), or asimilar dielectric film.

As shown in cross-sectional view 900 of FIG. 9A, a bottom electrodelayer 902 is deposited over the passivation layer 110 and into theopening 108 a, discussed above with respect to FIG. 7. In someembodiments, the bottom electrode layer 902 may be deposited by way of asingle, continuously deposition process. In other embodiments, thebottom electrode layer 902 may be deposited by way of a plurality ofdeposition processes performed in-situ (i.e., without breaking a vacuumof a deposition chamber in which the deposition processes areperformed).

In some embodiments, the bottom electrode layer 902 is comprised of aconductive material, such as, titanium nitride (TiN) or tantalum nitride(TaN), a metal (e.g., titanium (Ti) or tantalum (Ta) copper), etc. Thebottom electrode layer 902 may be formed to a thickness of approximately50 nanometers. Though not shown, in some embodiments, a diffusionbarrier layer may be deposited over the passivation layer 110 prior todepositing the bottom electrode layer 902.

In some embodiments, shown in cross-section view 904 of FIG. 9B, adiffusion barrier layer 204 may be deposited surrounding a lower metalvia 202. In such embodiments, the diffusion barrier layer 204 maycomprise diffusion barrier protrusions 204 a/204 b that propagatethrough one or more overlying layers during fabrication. For example,the dielectric protection layer 108 may have protrusions 206 a/206 blaterally arranged over the diffusion barrier protrusions 204 a/204 b,respectively. Likewise, the passivation layer 110 may have passivationprotrusions 208 a/208 b that are laterally arranged over the diffusionbarrier protrusions 204 a/204 b and dielectric protection protrusions206 a/206 b. Thus, when the bottom electrode layer 906 is deposited overthe passivation layer 110, the bottom electrode layer 906 has bottomelectrode protrusions 906 a/906 b.

As shown in cross-sectional view 1000 of FIG. 10A, the bottom electrodelayer 902 is planarized to remove excess conductive material, resultingin a planarized bottom electrode layer 1002 having a planar uppersurface 1002 u overlying the passivation layer 110. In some embodiments,the planarization may be performed using a chemical mechanicalplanarization (CMP) process. The CMP process may be a form of “light”CMP process performed to reduce the thickness of the bottom electrodelayer 902 from approximately 50 nanometers to 30 nanometers. In someembodiments, the light CMP process may be performed by bringing thesubstrate into contact with a polishing pad at a pressure that is lessthan that of the CMP process performed on the ILD layer 104.

As shown in cross-sectional view 1004 of FIG. 10B, the bottom electrodeprotrusions 906 a/906 b are removed by the CMP process resulting in aplanarized bottom electrode layer 1006 having a planar upper surface1006 u and a lower surface with depressions.

As shown in cross-sectional view 1100 of FIG. 11, a resistive switchinglayer 1102 is formed over the planarized bottom electrode layer 1002. Insome embodiments, the resistive switching layer 1102 may comprise amagnetic tunnel junction (MTJ) structure having a pinned magnetic layerand a free magnetic layer, which are vertically separated by adielectric barrier layer. In other embodiments, the resistive switchinglayer 1102 may comprise a RRAM dielectric data storage layer. In someembodiments, the resistive switching layer 1102 is approximately 3nanometers thick.

One or more top electrode layers 1104 are formed over the resistiveswitching layer 1102. The one or more top electrode layers 1104 compriseone or more conductive layers. In some embodiments, the one or more topelectrode layers 1104 include a first conductive layer 1106, a secondconductive layer 1108, a first hard mask layer 1110, and a thirdconductive layer 1112. The first conductive layer 1106, the secondconductive layer 1108, and the third conductive layer 1112 may becomprised of titanium nitride (TiN) or tantalum nitride (TaN), a metal(e.g., titanium (Ti) or tantalum (Ta) copper) etc. The first hard masklayer 1110 may be comprised of silicon nitride (SiN). In someembodiments, first conductive layer 1106 is approximately 15 nanometersthick, the second conductive layer 1108 is approximately 30 nanometersthick, the first hard mask layer 1110 is approximately 15 nanometersthick, and the third conductive layer 1112 is approximately 35nanometers thick.

In some embodiments, a plurality of hard mask layers 1114 are disposedover the one or more top electrode layers 1104. The plurality of hardmask layers 1114 includes a second hard mask layer 1116, a third hardmask layer 1118, and a fourth hard mask layer 1120. The plurality ofhard mask layers 1114 may be comprised of one or more of an advancedpattern film (APF), silicon oxynitride (SiON), etc. The second hard masklayer 1116 is approximately 130 nanometers thick, the third hard masklayer 1118 is approximately 200 nanometers thick, and the fourth hardmask layer 1120 is approximately 38 nanometers thick.

At least one patterning layer 1122 is formed over the plurality of hardmask layers 1114. The at least one patterning layer 1122 may include abottom antireflective coating (BARC) layer 1124 and a photoresist layer1126 which has been spin-coated over the BARC layer 1124 and patternedusing a double-patterning technique.

As shown in cross-sectional view 1200 of FIG. 12, the one or more topelectrode layers 1104 are patterned to form a top electrode 118 of thememory device 114 and the resistive switching layer 1102 is patterned toform a memory element 116 (i.e., a resistive switching element). In someembodiments, sidewalls of the memory element 116 and the top electrode118 can be tilted and linearly aligned (e.g., co-planar). In someembodiments, the patterning process can comprise a dry etching processthat may have an etchant chemistry including tetrafluoromethane (CF₄),difluoromethane (CH₂F₂), chlorine (Cl₂), boron trichloride (BCl₃),and/or other chemicals.

As shown in cross-sectional view 1300 of FIG. 13, a dielectric spacerlayer 128 is formed along an upper surface of the memory device 114including the planarized bottom electrode layer 1002. The dielectricspacer layer 128 may be comprised of silicon nitride, tetraethylorthosilicate (TEOS), silicon-rich oxide (SRO), or a similar compositedielectric film. In some embodiments, the dielectric spacer layer 128may be formed by a vapor deposition technique (e.g., physical vapordeposition, chemical vapor deposition, etc.).

As shown in cross-sectional view 1400 of FIG. 14, the dielectric spacerlayer 128 is patterned and removed from the memory device 114. In someembodiments, the patterning includes removing areas of the passivationlayer 110 and the planarized bottom electrode layer 1002 not underlyingthe memory device 114 to form a bottom electrode structure 112.Accordingly, sidewalls of the passivation layer 110 and the bottomelectrode structure 112 may be coplanar with the sidewalls of thedielectric spacer layer 128.

While the cross-sectional views corresponding to FIGS. 5-14 correspondto a memory region, the processes illustrated may also affect a logicregion of an IC. By forming the BEVA region 112 a and bottom electroderegion 112 b from the bottom electrode layer 902, additional BEVAplanarization and/or patterning processes are not needed, and thus donot affect the logic region.

FIG. 15 shows some embodiments of a flow diagram of a method 1500 offorming a flash memory device. Although method 1500 is described inrelation to FIGS. 5-14, it will be appreciated that the method 1500 isnot limited to such structures disclosed in FIGS. 5-14, but instead maystand alone independent of the structures disclosed in FIGS. 5-14.Similarly, it will be appreciated that the structures disclosed in FIGS.5-14 are not limited to the method 1500, but instead may stand alone asstructures independent of the method 1500. Also, while disclosed methods(e.g., method 1500) are illustrated and described below as a series ofacts or events, it will be appreciated that the illustrated ordering ofsuch acts or events are not to be interpreted in a limiting sense. Forexample, some acts may occur in different orders and/or concurrentlywith other acts or events apart from those illustrated and/or describedherein. In addition, not all illustrated acts may be required toimplement one or more aspects or embodiments of the description herein.Further, one or more of the acts depicted herein may be carried out inone or more separate acts and/or phases.

At 1502, an inter-layer dielectric (ILD) layer is formed over asubstrate. In some embodiments, formation of the ILD layer is followedby a damascene process to form openings within the lower ILD layer andfill those openings with a metal material (e.g., copper, aluminum, etc).

At 1504, a dielectric protection layer is formed over the ILD layer. Thedielectric protection layer is patterned to have an openingcorresponding to formation of BEVA FIGS. 5-7 illustrate some embodimentsof a cross-sectional views 500, 600, and 700 corresponding to act 1504.

At 1506, a bottom electrode layer is formed over the dielectricprotection layer and the opening in the dielectric protection layer.FIG. 9 illustrates some embodiments of cross-sectional view 900corresponding to act 1506.

At 1508, a chemical mechanical planarization (CMP) process is performedon the bottom electrode layer until the bottom electrode layer issubstantially planar. A BEVA region and a bottom electrode region areboth formed from the bottom electrode layer. FIG. 10 illustrates someembodiments of a cross-sectional view 1000 corresponding to act 1508.

At 1510, a resistive switching layer is formed over the planarizedbottom electrode layer. FIG. 11 illustrates some embodiments of across-sectional view 1100 corresponding to act 1510.

At 1512, one or more top electrode layers are formed over the resistiveswitching layer. FIG. 11 illustrates some embodiments of across-sectional view 1100 corresponding to act 1512.

At 1514, the resistive switching layer and the one or more top electrodelayers are patterned to form a resistive switching element and a topelectrode. FIG. 12 illustrates some embodiments of a cross-sectionalview 1200 corresponding to act 1514.

At 1516, a dielectric spacer layer is formed over the resistiveswitching element and the top electrode. The dielectric spacer layer hasspacer layer sidewalls. FIG. 13 illustrates some embodiments of across-sectional view 1300 corresponding to act 1516.

At 1518, an etching process is performed on the planarized bottomelectrode layer to form a bottom electrode structure having bottomelectrode sidewalls that are coplanar with the spacer layer sidewalls.FIG. 14 illustrates some embodiments of a cross-sectional view 1400corresponding to act 1518.

It will be appreciated that while reference is made throughout thisdocument to exemplary structures in discussing aspects of methodologiesdescribed herein that those methodologies are not to be limited by thecorresponding structures presented. Rather, the methodologies (andstructures) are to be considered independent of one another and able tostand alone and be practiced without regard to any of the particularaspects depicted in the FIGS. Additionally, layers described herein, canbe formed in any suitable manner, such as with spin on, sputtering,growth and/or deposition techniques, etc.

Also, equivalent alterations and/or modifications may occur to thoseskilled in the art based upon a reading and/or understanding of thespecification and annexed drawings. The disclosure herein includes suchmodifications and alterations and is generally not intended to belimited thereby. For example, although the figures provided herein areillustrated and described to have a particular doping type, it will beappreciated that alternative doping types may be utilized as will beappreciated by one of ordinary skill in the art.

In some embodiments, the present disclosure relates to a method ofmanufacturing an integrated circuit (IC). The method comprises formingan inter-layer dielectric (ILD) layer over a substrate. An opening isformed within a dielectric protection layer over the ILD layer, and abottom electrode layer is formed within the opening and over thedielectric protection layer. A chemical mechanical planarization (CMP)process is performed on the bottom electrode layer to form a bottomelectrode structure having a planar upper surface and a projection thatprotrudes outward from a lower surface of the bottom electrode structureto within the opening. A memory element is formed over the bottomelectrode structure and a top electrode is formed over the memoryelement.

In another embodiment, the present disclosure relates to a method ofmanufacturing an integrated circuit (IC). The method comprises forming aplurality of metal layers within an inter-layer dielectric (ILD) layerover a substrate, and forming a dielectric protection layer over the ILDlayer. The dielectric protection layer has an opening overlying one ofthe plurality of metal layers. A conformal passivation layer is formedover the dielectric protection layer and the opening and a bottomelectrode layer is deposited over the conformal passivation layer andwithin the opening. A chemical mechanical planarization (CMP) process isperformed on the bottom electrode layer to form a planarized bottomelectrode layer having a substantially planar upper surface. Theplanarized bottom electrode layer has a bottom electrode via (BEVA)region and a bottom electrode region. A resistive switching element isformed over the bottom electrode layer and a top electrode is formedover the resistive switching element. A dielectric spacer layer isformed over the resistive switching element and the top electrode. Thedielectric spacer layer has spacer layer sidewalls. An etching processis performed on the planarized bottom electrode layer to form a bottomelectrode structure having bottom electrode sidewalls co-planar with thespacer layer sidewalls.

In yet another embodiment, the present disclosure relates to anintegrated circuit (IC). The IC includes a dielectric protection layerdisposed over an ILD layer. The dielectric protection layer has anopening overlying a metal layer surrounded by the ILD layer. Apassivation layer is disposed over the dielectric protection layer andwithin the opening. A bottom electrode structure is disposed over thepassivation layer. The bottom electrode structure includes a bottomelectrode via (BEVA) region and a bottom electrode region. A height ofthe bottom electrode region extends from an upper surface of thepassivation layer to a top surface of the bottom electrode structure,and a lower surface of the bottom electrode structure has notchescorresponding to protrusions in the passivation layer. A resistiveswitching element is arranged over the bottom electrode structure, and atop electrode is arranged over the resistive switching element.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An integrated circuit, comprising: a dielectricprotection layer disposed over a dielectric structure, wherein thedielectric structure laterally surrounds one or more conductiveinterconnect layers, and wherein the dielectric protection layercomprises a protrusion extending outward from an upper surface of thedielectric protection layer; a bottom electrode disposed over thedielectric protection layer and having sidewalls extending outward froma lower surface of the bottom electrode through the dielectricprotection layer, wherein the bottom electrode has a planar uppersurface over the protrusion; a data storage element over the planarupper surface of the bottom electrode; and a top electrode over the datastorage element.
 2. The integrated circuit of claim 1, furthercomprising: a passivation layer between the dielectric protection layerand the bottom electrode, the passivation layer having a secondprotrusion extending outward from an upper surface of the passivationlayer.
 3. The integrated circuit of claim 1, wherein the data storageelement is arranged directly above a bottommost surface of the bottomelectrode.
 4. The integrated circuit of claim 1, wherein the bottomelectrode has a first thickness at a center of the bottom electrode, asecond thickness along an outermost sidewall of the bottom electrode,and a third thickness laterally between the center and the outermostsidewall; and wherein the second thickness is smaller than the firstthickness and larger than the third thickness.
 5. The integrated circuitof claim 1, wherein the data storage element comprises a magnetic tunneljunction.
 6. The integrated circuit of claim 1, wherein the bottomelectrode comprises a same material that continuously extends from abottommost surface of the bottom electrode to a topmost surface of thebottom electrode.
 7. An integrated circuit, comprising: a dielectriclayer disposed over a dielectric structure, wherein the dielectricstructure laterally surrounds one or more conductive interconnects; abottom electrode disposed between sidewalls of the dielectric layer andover the dielectric layer, wherein the bottom electrode comprises aconductive material, wherein the bottom electrode has a bump portionbetween a central portion and an outer portion, wherein the centralportion includes a center of the bottom electrode, and wherein the bumpportion has a first maximum thickness is smaller than a second maximumthickness of the outer portion; a memory element over a flat uppersurface of the bottom electrode; and a top electrode over the memoryelement.
 8. The integrated circuit of claim 7, further comprising: apassivation layer between the dielectric layer and the bottom electrode,the passivation layer having one or more surfaces defining a firstprotrusion extending outward from an upper surface of the passivationlayer.
 9. The integrated circuit of claim 7, wherein the dielectriclayer has one or more surfaces defining a protrusion extending outwardfrom an upper surface of the dielectric layer.
 10. The integratedcircuit of claim 9, wherein the bottom electrode has a smallestthickness directly over the protrusion.
 11. The integrated circuit ofclaim 9, wherein the flat upper surface of the bottom electrode isdirectly over the protrusion.
 12. The integrated circuit of claim 7,wherein the conductive material is titanium nitride or tungsten.
 13. Anintegrated circuit, comprising: a passivation layer disposed over adielectric structure, wherein the dielectric structure laterallysurrounds one or more conductive interconnects, and wherein thepassivation layer defines a bump that protrudes outward from an uppersurface of the passivation layer; a bottom electrode disposed betweensidewalls of the passivation layer and directly over the bump, whereinthe bottom electrode comprises a conductive material, and wherein theconductive material has an upper surface extending between outermostsidewalls of the bottom electrode; a data storage layer arrangeddirectly over a bottommost surface of the bottom electrode; and a topelectrode arranged over the data storage layer.
 14. The integratedcircuit of claim 13, further comprising: a dielectric protection layerdisposed between the dielectric structure and the passivation layer,wherein the dielectric protection layer defines a protrusion directlybelow the bump.
 15. The integrated circuit of claim 14, wherein a top ofthe passivation layer is above a top of the dielectric protection layer.16. The integrated circuit of claim 14, wherein the passivation layerlines sidewalls of an opening within the dielectric protection layer.17. The integrated circuit of claim 16, wherein the passivation layercontinuously extends from a top surface of the dielectric protectionlayer to the sidewalls of the opening.
 18. The integrated circuit ofclaim 13, wherein the bottom electrode has a smallest thickness directlyover the bump.
 19. The integrated circuit of claim 13, wherein animaginary horizontal line, which is parallel to an upper surface of thedielectric structure, extends through sidewalls of both the bump and thebottom electrode.
 20. The integrated circuit of claim 13, wherein thebottom electrode has a first thickness directly above the bump and asecond thickness laterally between the bump and a first one of theoutermost sidewalls of the bottom electrode, the first thickness smallerthan the second thickness.